1. Field
The present invention relates to a communication apparatus such as a cell phone which car perform kinds of communication corresponding to different radio access technologies.
2. Description of the Related Art
UMTS (universal module telecommunications system), GRM (global system for mobile communications), etc. are employed as the above-mentioned radio access technologies (RATs) Among these technologies, UMTS is employed in Japan and known as WCDMA (wideband code division multiple access).
A cell phones (refer to JP-A-2006-217268) capable of receiving an overseas roaming service are equipped with a communication section which can accommodate both of the above-mentioned UMTS and GSM, and is configured in such a manner that the user himself or herself sets, through a setting picture of the cell phone, information of radio access technology employed by a communication company that operates a network in each country. Such setting is called RAT setting.
Such a cell phone capable of receiving an overseas roaming service is associated with a problem that if the user goes to a country where only GSM is supported with the RAT setting made to an UMTS only mode, no communication can be performed because of improper setting though the cell phone has a GSM communication function. To avoid this problem, an UMTS/GSM dual mode is provided.
If the RAT setting is made to the dual mode, a communication can be performed by a cell phone having the above function in either of a case that the user goes to a country where only UMTS is supported and a case that the user goes to a country where only GSM is supported. However, if the RAT setting is made to the dual mode, a radio wave search which accommodates both radio access technologies (UMTS and GSM) is performed every time. This results in a problem that the radio wave search time is long and the power consumption is increased.